. >>> tomorrow president hamid karzai of afghanistan will meet with president obama of the white house. when to keep u.s. troops in afghanistan when their mission comes to an end, and if so, how many. it's an issue senator lindsey graham says is key to america's success in the region. >> the possible solutions have a small footprint left behind in afghanistan where they become sitting ducks and it will lead to failure. we've fought too hard, too long to not get things right. his decision about a 2014 force will affect national security for decades. i'd like to support the president if it's a robust number. tha thanh, good evening your time. karzai has a key role in the status of the troops in the region. what is that exactly? >> reporter: alex, a lot of what's going to happen here in afghanistan post-2014 may hinge on this notion of immunity and president karzai and what he decides to do with that. that immunity would basically give legal protection for whatever force is left behind here in afghanistan, and it would give legal protection for those troops in the event they break local l